State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2017 Aug 15;7(1):8213. doi: 10.1038/s41598-017-08476-y.
The molecular analysis of sex in vertebrates is important, as it has the potential to provide vital information for theoretical and applied research alike. Teleost fish are the ancient vertebrates that present a broad sex chromosome system but lack differentiated sex chromosomes in most species. Hence understanding the sex in fish would not only illuminate the sex determination evolution in vertebrates but also shed light on fish farming. In the present study, we used grass carp as a teleost fish model, studied the Y chromosome by using a pool-and-sequence strategy in combination with fragment-ratio method. In total, we identified five Y-linked scaffolds (totaling 347 Kb) and six Y-specific sequences that could be used as sex-specific markers, demonstrating the suitability of NGS-based re-sequencing of pooled DNAs for the identification of sex markers in fish. Moreover, 14 putative Y-linked genes were described for the first time. All the genes, except for un-y1, un-y2, and ubq-y, showed high similarity to their female homologs. RT-PCR revealed that ubq-y was only expressed in the male hypothalamus and pituitary. These findings provided an abundant resource for the Y chromosome of grass carp, and may help elucidate sex chromosome evolution in cyprinid fish.
脊椎动物的性别分子分析很重要，因为它有可能为理论和应用研究提供重要信息。硬骨鱼是古老的脊椎动物，具有广泛的性染色体系统，但在大多数物种中缺乏分化的性染色体。因此，了解鱼类的性别不仅可以阐明脊椎动物的性别决定进化，还可以为鱼类养殖提供启示。在本研究中，我们以草鱼为硬骨鱼模型，采用池测序策略与片段比法相结合，研究 Y 染色体。总共鉴定出 5 个 Y 连锁支架（总计 347kb）和 6 个可作为性别特异性标记的 Y 特异性序列，证明了基于 NGS 的混合 DNA 重测序用于鉴定鱼类性别标记的适用性。此外，首次描述了 14 个假定的 Y 连锁基因。除了 un-y1、un-y2 和 ubq-y 外，所有基因与雌性同源物都具有高度相似性。RT-PCR 显示 ubq-y 仅在雄性下丘脑和垂体中表达。这些发现为草鱼的 Y 染色体提供了丰富的资源，可能有助于阐明鲤科鱼类的性染色体进化。
